1. Field of the Invention
Heating systems wherein the heat source is a reverse cycle refrigeration unit or heat pump, said systems being generally classified in Class 237, Subclass 2B.
2. The Prior Art
G. Sartorius (U.S. Pat No. 3,786,161) titled "Process and Apparatus for Monitoring and Control of Metallurgical Furnaces" discloses a concept for controlling a furnace as a function of the rate of temperature change. This, however is a very general teaching and fails to deal with the specific problems encountered in the design of heat pump systems and the control of supplemental heat.
W. Iberg et al (U.S. Pat. No. 3,993,120) titled "Space Thermostat" is directed to the concept of single thermostat adapted to control, in a selective manner, two stages of a multiple stage heating apparatus. The temperature sensing element is a bimetallic coil which does not measure the rate of temperature change and therefore differs in principle from the present invention.
A. Kompelien (U.S. Pat. No. 3,586,869) titled "Sequencing Control Unit" concerns a system utilizing solid state switching devices for sequencing stages of electric heat. The thermostat, however, is not of the type that can determine the rate of change of the temperature in the controlled space.